The US public largely backs the Pentagon's decision to lift restrictions on women in combat, a poll showed on Tuesday.

Sixty-six percent of those polled said they support letting women serve in ground units that engage in close combat, while 26 percent are opposed, according to the survey by the Pew Research Center for the People & the Press and the Washington Post.

Opinion on the issue is little changed from a Washington Post/ABC News survey two years ago, Pew said in a statement.

The Defense Department lifted a long time ban on women serving in front-line combat units on Thursday. The move marked a historic step toward sexual equality after 11 years of war in which women were increasingly on the battlefield.

The survey found that the public is split over whether the move represented a major change for the U.S. military. Forty-seven percent said it is, while an equal percentage said it is a minor change.

The poll was conducted from Jan. 24 to 27 among 1,005 adults, after Defense Secretary Leon Panetta ended the combat ban. The margin of error was 3.7 percentage points.

The poll found that 58pc of Americans think that the policy shift will improve opportunities for women in the military.

Nearly half, or 49pc, say allowing women to serve in combat roles will not make much difference to military effectiveness.

Among those who say it will have an impact, 29pc say this will improve effectiveness, versus 15pc who say it will make it worse.